Address all correspondence to:The Chief Executive

22 December 2013

Otago Regional CouncilPrivate Bag 1954DUNEDIN 9054

Dear Sir/Madam

CLUTHA DISTR UNCIL2

Our ReferenceqA56

Waihola Sewage Treatment Plant Discharge to Lake Waihola Outlet Channel: Resource Consent

I enclose the above application on behalf o f Council, together with cheque for thedeposit.

This application is to replace the current consent, which expires on 1 September 2017. While anapplication is not required until 1 2017 to protect the current right to while areplacement consent is processed, the existing plant does not comply with current consent conditionson many occasions. Council has decided to upgrade the treatment at the site with a long term consent inview, so is seeking a new, long−term consent in order to establish it must meet.

At the same time, Council has received proposals to upgrade the plant to meet quality limitssuggested by this application, but will await the outcome o f this application before committing itself toa particular upgrade.

Please read letter as forming a part o f the application for a new consent, taking particular note ofthe above circumstances.

Please contact me i f you have any

Yours faithfully

Peter RossPROJECTS ENGINEER

1 Rosebank TerraceP 0 Box 25, Balclutha 9240, New ZealandTelephone + 4183185Email:Website: www.cluthadc.govt.nz

***Copy***

Otago Regional Council GST NO. 51−688−775

Receipt No. 375413

CONConsent Deposits

CLUTHA DISTRICT COUNCIL

14:30:39

1,000.00

Cheque 117995 −1,000.00Payment

ReceiptAmount Tendered:Change Given:Rounding Amount:

1,000.001,000.00

CLUTHA DISTRICT COUNCIL

WAIHOLA SEWAGE TREATMENTPLANT

Application to Discharge Treated Sewage Effluentto the Lake Waihola Outlet Channel

22 December 2015

APPLICATION FOR RESOURCE CONSENTPURSUANT TO SECTION 88 OF THE RESOURCE MANAGEMENT ACT

1991

To: Chief ExecutiveOtago Regional CouncilPrivate Bag 1954Dunedin 9054

By: Clutha District Council1 Tce

Box 25Balclutha 9240

Clutha District Council applies for the renewal of the resource consentdescribed below.

1. The resource consent sought is a discharge permit to dischargecontaminants to water, pursuant to Section 15 of the RMA.

The consent term sought is 35 years.

2. The activity to which this application relates is:

To discharge up to 680m3 of treated sewage per day to the outflowchannel of Lake Waihola.

Refer to the Assessment of Environmental Effects (AEE) for furtherdetails about the proposed activity.

3. The location to which this application relates is the true right bank of theLake Waihola outflow channel, approximately 1.4 km upstream of theState Highway 1 Bridge across the outflow channel.

The grid reference of the discharge point is NZTM 1376557E 4902692N.

The Waihola Sewage Treatment Plant is situated on Titiri Rdapproximately 1.9km of Waihola.

The legal description of the land at the point of discharge is Section 1,Survey Office Plan 24904, or Lot DP 27225, or riverbed. The first is astrip between the second and last, and it is unclear whether thedischarge point is within the strip or not. Refer to the AEE for a site plan.

4. The name and address of the landowner, to which the applicationrelates, is:

The CrownLand information New Zealand

Lakes Property ServicesBox 1586

Queenstown.

5. No additional resource consents are required in relation to theproposal.

6. An assessment of environmental effects of the proposal is attached.

7. Information required by the Regional Plan: Water for Otago is attached.

Peter RossWater Engineer (ProjectsClutha District Council

Date:

Address for Service

Clutha District CouncilBox 25

Balclutha 9240

Attention: Peter Ross, Water Services Engineer (Projects)

Tel: 0200Fax: 3185

Email:

1. INTRODUCTION

1.1 Overview

Clutha District Council currently holds Consent No. 2002.046 which authorisesthe discharge of treated sewage to the Lake Waihola outflow channel. Thisconsent expires on 1 September 2017. This application is to replace thatconsent and there is no change in the location or purpose of the activity forwhich consent is sought from that covered by Consent No. 2002.046.

Consent 2002.046 authorises the discharge of up to 680m3 per day as anormal flow and up to as a wet weather flow.

This application describes the current operation of the plant and details thevolume and character of the discharge for which consent is sought.

Further details are provided in the appropriate sections of this AEE.

1.2 Regional Plan Provisions

This is a discharge of human sewage to water which is envisaged by Rule12.6 of the Regional Plan: Water Plan) which has not been amended byPlan Change 6A. The discharge does not meet any of the permitted activitycriteria in Rule 12.6.1, set out in Rules 12.6.1.1 to 12.6.1.4.

Rule 12.6.2.1 of the Plan provides that "Except as provided for by Rules12.6.1.1 to 12.6.1.4, the discharge of human sewage to water, or onto land incircumstances where it may enter water is a discretionary activity."

Accordingly, the discharge is a discretionary under the ofthe Plan.

1.3 Appendices

The following Appendices are attached:

• Appendix 1: Copy of Consent No. 2002.046.• Appendix 2: Discharge monitoring results.• Appendix 3: Ryder Consulting, Waihola Oxidation Pond Discharge to

the Lake Outflow Channel Assessment ofEnvironmental Effects, 2014.

Appendix 4: Webb, Trevor, Soil Investigation to evaluate Capability ofland Surrounding Stirling, Kaitangata,Owaka, Clinton, Heriot and Lawrence for Use asMunicipal Wastewater Disposal Sites (Manaaki WhenuaLandcare Research, 2007).

2. ENVIRONMENTAL SETTING

2.1 Site Location

The Waihola Sewage Treatment Plant is located on Titri Road, approximately1.9km north of Waihola. After treatment, effluent is discharged through anoutlet pipe which extends northwards to the true right bank of the LakeWaihola Outflow Channel. The discharge point is most likely located withinSection 1, Survey Office Plan 24904, which is a strip between riverbed andLot DP 27225. See Figure 3 below for a detail. The treatment plant site itself isLot 1 DP 20844 and is owned in fee simple by the Clutha District Council. Thissite is designated for sewage treatment in the Clutha District Council'soperative District Plan.

The Waihola Treatment Plant consists of a single oxidation pondapproximately 3,800m2 in area and a surface flow wetland which has twoparallel cells of Sewage is collected within Waihola through a gravityreticulation which conveys it to a pump station situated in the WaiholaDomain. From there it is pumped to the treatment plant, with additionalsewage being introduced by a small pump station serving on the

extremity of Waihola. The sewage goes through the oxidation pondand wetland in series before being discharged to the outflow channel.

The discharge to the outflow channel is pumped from a small pump station onthe treatment plant site, with discharge being limited to the latter half of theincoming tide and the initial half of the outgoing tide. This regime is requiredby Condition 2(a) of the existing consent, and is designed to preventconditions where treated sewage might be carried by the tide from the outfallinto Lake Waihola.

Metering of the incoming flow is achieve via a meter on the outlet from themain pump station, and also one on the outlet from the small pump stationserving Waihola. Records are available from these meters from earlyFebruary 2013, since when the flow from the main pump station has averaged85m3/d and that from the Waihola pump station 8 m3/d, a total of 93m3/d

conveyed to the sewage treatment plant. The lowest total recorded wason 5 May 2015 and the highest 773m3 on 5 June 2015. The effluent

flows in series through the oxidation pond and then through one or other ofthe wetland cells.

Over the same period, the from the plant has averaged 102m3/d, thedifference from the inflow being accounted for by rainfall. Peak dischargeshave occurred when the control system has malfunctioned or pumping wasforced for 24 hours a day because of high inflows, as happened in June 2015.The peak recorded has been 369m3 under those circumstances. During timesof normal operation, the maximum daily discharge was

4

Figure 1: Waihola Sewage Treatment Plant

Lake Waihola Outflow Channel

Figure 2: Site Plan and Discharge Point Location

Outfall pipe andex CDC GIS

Figure 3: Outfall Location Detail

Figure 4: Outfall Site, Viewed f rom the Centre o f the Outlet Channel (left) and bank(right).

The outfall is a 100mm internal diameter high density polyethylene pipeanchored to the bottom of the channel, extending 24m from the true right(southern) bank. There are seven 40mm diameter ports at centres at thetop of the outfall pipe over the last 6.35m of the outfall pipe. The outletchannel is approximately 5m deep at the end of the outfall pipe.

2.2

Currently there are 172 properties connected to the reticulation, including thecamping ground. A further 60 properties pay a half rate and so have a right toconnect to the reticulation should they be developed.

since 2013 are available, and these incorporate somedays of low flow from Waihola and, in June 2015, historically very high flowsfrom the township.

Because the outflow is pumped at specific times, the usual daily maximum isgoverned by what times are actually pumped and the pump flow itself. Thepumping period varies between 6h 9m and 6h 18m depending on theparticular tide. At present, the pumped flow is around 3.80 which gives anaverage total flow per pumping period of 85m3. Some days will have twocomplete pumping periods, and others will not, so the maximum volume ableto be pumped in one day is 170m3 at this pumped flow. Other days with lessthan two complete cycles will have a lower volume. Pump flows will also beaffected to some extent by the level in the Outlet Channel itself — lower levelswill produce somewhat higher flows.

The pump is also controlled by the level in the wetland outlet. So, the tidetimes dominate, but if levels are too low in the wetland, the pump will notoperate, or will stop if the low level "stop" is reached during a pumping period.This means that volumes discharged can be less, indeed much less, thanthose noted above.

The volumes can occasionally be higher if flows to the wetland or pondoverwhelm the system. This can happen if stormwater from the surroundingarea enters the wetland, which is possible if rainfall intensities are highenough. Equally, high flows can occur form the township itself. On theseoccasions, the pump operates continuously and the 24 hour flow can reach330m3 or more.

Flows are summarised in Table 1 below. Note that the theoretical figures arecalculations of the flow generated by the town and take no account of rainfallon the pond or evaporation from it. However, 100mm of rain will generate380m3 of rain on the pond, so while it may be significant on a wet day, itis not a significant contributor to the average flow. Overall, the annual averagerainfall of about 750mm contributes less than 8m3/d averaged across the year.

ParameterMeasured Average Daily Discharge 102Maximum Daily Discharge 3461Minimum Flow 31Theoretical Weather Inflow2 67Theoretical Average Inflow3 292Measured Average Inflow 93Theoretical Maximum Daily Inflow3 1,942Measured Maximum Inflow 773Flows over were recorded between 18 and 22 June 2013. These are likely tobe due to a telemetry fault rather than be actual flows.

2 Based on a permanent population of 335 (2013 Census) and 200Based on Hamilton City Council, Hamilton City Design Manual; Volume 2 — DesignGuide; Part 5 — Wastewater Drainage, 2011. The volumes include allowances for anaverage discharge of 200 L/person/d, infiltration of 2,250 L/ha/d and surface wateringress of 16,500 L/ha/d.

7

Table 1: Waihola Sewage Flows

The theoretical maximum daily flow has a substantial contribution fromsurface water ingress. The Hamilton City Council design manual addressesnew developments, but is obviously applicable to the general urbanenvironment. However, the density of development contemplated in themanual is certainly much higher than the present density in Waihola, so thetheoretical dry weather average flow and maximum flow above will besignificantly overstated. The dry weather average flow figure will be inflatedbecause of the lower density of reticulation will mean less infiltration.1 Themaximum flow will be inflated because a much higher proportion of the area inWaihola will absorb water than in the usual urban setting, thusreducing the amount of water which could enter the sewagereticulation.

This can be seen in the actual density of connected to the sewagereticulation. The town extends to approximately 100 ha within which 172

are connected to the reticulation. This is 5,800m2/property,approximately three times the 1,900m2/property in for example. Inview of the intensity of the event in June 2015, the maximum flow measured inthe meter record is likely to be a good representation of the maximum dailyflow to the sewage treatment plant..

Sewage flows typically increase in wet weather compared to weather, dueto the ingress of stormwater to the reticulation. This comes from illegalconnections (eg downpipes connected to gully traps) and from flowfinding its way into the system via gully traps without sufficient surrounds,manhole lids, cleaning eye lids, etc. In addition, groundwater can get into thereticulation through poorly sealed joints, manholes and wetwells, anddamaged pipes. This latter source becomes more prevalent as a systemages.

Stormwater cannot be entirely excluded from sewage reticulation, and this isrecognised in the typical ratio of wet weather flow to weather flow. In anew, system, the ratio of wet weather flow to averageweather flow can be expected to be around 3, with action on infiltrationindicated when wet weather flow exceeds 5 times the average weatherflow.

The metered flows above indicate that this ratio reached a maximum of 8.3,but this only applies to a day of exceptional rainfall. There is no indication thatinvestigation and action on infiltration is required: see the discussion in 6.below.

When considering the discharge volumes sought, the question of thepossibility of future growth in Waihola needs to be considered. The abovediscussion indicates that a discharge volume of about 350 m3/d could beappropriate at present.

There will be less pipe length per hectare, so less joins and less opportunity for faults and lessmanholes, etc, than in a development with a higher density.

8

To some extent, the actual volume discharged in the future will also dependon the type of additional treatment chosen. Some technologies incorporate aplant with a set treatment capacity, and hence a fairly stable discharge flow,where the existing system is used to buffer the flow. Others will still dischargea wide range of daily volumes. It may also be that additional treatmentalternatives may not require the existing wetland in which case the bufferingcapacity of the system will reduce and the variability discharge volumesincrease.

The actual volume that can be discharged is governed by the pump capacity,so a limit applies at present. While it is of a certain capacity at present, it couldbe replaced with a pump capable of a higher flow, so discharge volumes couldincrease.

At the present instantaneous flow rate of 3.8 pumping for two tide cyclesgives a daily discharge of 171 m3. On occasions of very high inflows, it hasbeen necessary to pump continuously to prevent the pond or wetlandoverflowing into the stream skirting the site. At this flow rate, pumping for 24hours will give a total discharge of 328 m3, consistent with the maximum

in Table 1, given the variables in the system.

In addition, Waihola is one location within the Clutha District where somegrowth has occurred and might be expected in the future. This would increasethe effluent flow from the township.

Considering these factors and bearing in mind peak inflow, it is prudent toleave the consent volume at the current rate of 680 m3/d, hence that isthe volume sought.

Lake Waihola Outlet Channel

The hydrology of the Lake Outlet Channel is described in Ryder.2 It isone of a network of channels connecting Lakes Waihola and Waipori and theTaieri and Waipori Rivers. Groundwater and the Taieri Main Drain alsoprovide water to the system.

The Outlet Channel is tidal, with one third of the volume of Lake Waiholatypically displaced in a typical tidal cycle (about 2,400,000m3). The daily netflow can be either upstream or downstream, depending on tides andfreshwater inputs. The channel is 60−90m wide and up to 8m deep in thevicinity of the outfall.

There is no flow data for the channel, but the volume and annual hydraulicresidence time of Lake Waihola suggests an average of 0.55 m3/s.The present discharge is approximately 0.7% of this flow. While, because ofthe tidal nature of the channel, it is not simply a matter of considering the

2 Ryder Consulting, Oxidation Pond Discharge to the Lake Waihola Channelo f Environmental February 2014, 9−10.

9

discharge against this flow, clearly the volume dischargedcompared to other influences on the channel.

2.3.1 Sea Level Rise

Because the Outlet Channel is tidal, sea level rise will affect the hydraulics ofthe treatment plant outfall. At the end of the term sought for the consent(2050), sea level is predicted to be 300mm above present levels.3 Without any

change, this is calculated to reduce the flow from 3.80 to 3.70 L/s.This is a minor change, but could easily be accommodated, if necessary, byupgrading the pump to one of a higher capacity. Sea level change will have aless than minor impact on the treatment plant.

2.3.2 Ecological Values

Lakes Waihola and Waipori are identified in Schedule 1A of the RPW ashaving particular ecological values, which are summarised in Table 2..

Water body Ecosystem values

Lakes Waipori/Waihola Large water bodies supporting high numbers of particular species, orhabitat variety, which can provide for diverse life cycle requirements of aparticular species, or a range of species

Access within the main stem of a catchment through to the sea or a lakeunimpeded by means, such as weirs, and culverts

Silt bed composition of importance for resident biota

Free of aquatic pest plants (e.g. Lagarosiphon) identified in the PestManagement Strategy for Otago 2009.

Presence of riparian vegetation of to aquatic habitats

areas for:• Trout spawning• Development of juvenile trout

Significant presence of:• Trout

Eels

Presence of a range of indigenous fish (including giantand indigenous waterfowl (including a breeding population of fernbird)

Presence of a significant range of indigenous fish species and waterfowlthreatened with extinction.

Table 2: Schedule Values, Lakes Waihola and Waipori4

The of Conservation identified in 1993 that theLake — Wetland complex is a coastal system of great ecological importance.5

Climate Change 2013: The Physical Science Basis. Working Group I contribution to the IPCCAssessment Report; Projections o f Level Rise, IPCC, 2013, 8.

Taken Ryder, 7Department o f Conservation, Lakes Waipori and Waihola Wetland: a natural resources

Otago Dunedin, 1993. Cited in Ryder, 5.

0

2.3.3 Cultural Values

Schedule of the RPW identifies the cultural values associated with Otago'swaters. Lakes Waihola and Waipori are identified in Schedule of the RPWas having particular cultural values, coupled with the Sinclair Wetlands. Thesevalues are listed in Table 3.

Beliefs, values and uses Explanation

Pomahaka River

Mana interests MA1: Kaitiakitanga The exercise of guardianship by KaiTahu in accordance with tikanga Maori inrelation to Otago's natural and physicalresources; and includes the ethic ofstewardship

MA2: Mauri Life force; for example the mauri of ariver is most recognisable when there isabundance of water flow and theassociated ecosystems are healthy andplentiful; a most important element in therelationship that Kai Tahu have with thewater bodies of Otago

MA3: Waahi tapu and/or Sacred places; sites, areas and valuesWaiwhakaheke associated with water bodies that hold

spiritual values of importance to KaiTahu. (Note: Kai Tahu should beconsulted regarding the location of theseplaces, sites areas and values for a riveridentified as MA3)

MA4: Waahi taoka Treasured resource; values, sites andresources that are valued and reinforcethe special relationship Kai Tahu havewith Otago's water resources

Access/customary use MB1: Mahika kai Places where food is procured orinterests produced

MB2: Kohanga Important nursery/spawning areas fornative fisheries and/or breeding groundsfor birds

MB3: Trails Sites and water bodies which formedof traditional routes

MB4: Cultural materials Water bodies that are sources oftraditional weaving andmedicines

MB5: Waipuna Sources of water highly regarded fortheir purity, healing andpowers.

Table 3: Schedule Values, Lakes Waihola and Waipori6

Ryder, 8

11

2.4 Description of Activity

The present activity is the treatment of municipal sewage, comprising almostexclusively domestic sewage, in a single conventional oxidation pond followedby a surface flow wetland in series. This treatment process is simple androbust, and produces an effluent with the characteristics given in Table 4.

Parameter Geomean 90th Percentile

BOD5 39 100

Total Phosphorus 5.90 11.03

Ammoniacal Nitrogen g/m3 16.5 41.0

Suspended Solids g/m3 81 239

Faecal Coliforms 7,006 48,700

pH (geomean and range) 7.44 6.69 — 9.03

Table 4: Waihola Sewage Treatment Plant Characteristics

These characteristics are taken from the consent monitoring done by CluthaDistrict Council at three monthly intervals from May 2004 to November 2015,plus occasional other sampling in the period, comprising 53 samples all told.The last sample in the record was taken in November 2015. The monitoringresults are given in Appendix 2.

The discharge is a 100mm diameter pipe with ports, fixed to the bed of theOutlet Channel as shown in Figure 4 and described in 2.2 above. The volumedischarged is small relative to the net Channel flow.

Clutha District Council has not sampled the outlet channel, as this is notrequired by the current consent. In addition the fact that flow occurs in bothdirections depending on the state of the tide makes sampling upstream anddownstream of the outfall somewhat meaningless as a way of evaluating theimpact of the discharge on the Channel. Ryder that there is little waterquality data for the Channel and suggests that water quality in Lake Waiholaitself is the best indicator available for the Outlet Channel. He notes that thelake is supertrophic, saturated in phosphorus and nitrogen. The former hastrended up in recent years, while the latter has trended down, but the lake isnitrogen limited. Turbidity in the lake is usually high and the lake has a highpercentage of saturated oxygen with low E.coli levels which mean the lake isusually safe for swimming. However, the high nutrient loads can promote algalblooms, when it becomes unsafe for swimming.

3. Consent Term

A 35 year consent term is sought is sought for the following reasons:

12

• Section 4 of the report below indicates that alternative treatmentmethods and locations have been considered. Continuation of thepresent point discharge is the only practicable option.

• Section 5 of the report below confirms that any adverse effects on theOutlet Channel are minor.

• To provide long term security of service at an acceptable cost for theratepayers who are customers of the service.

4 Consideration of Alternatives

The Schedule of the RMA requires a description of possible alternativelocations or methods for the activity, where it is likely that anactivity will result in any significant adverse effect on the environment. In thiscase, while there are alternative treatment methods to improve the quality ofthe effluent, the final disposal will only be to water or to land. Accordingly,these are the alternatives considered.

Discharge to Land

A discharge to land would require the purchase of suitable land and itsdevelopment, plus conveyance of the effluent to the site. In 2007, TrevorWebb of Landcare Research evaluated land in the vicinity of Waihola forsuitability to use for the disposal of treated sewage effluent. The area to beevaluated was defined as all land within a 3.75km radius of Waihola. Disposalof treated sewage effluent to land is governed by the capacity of the land totreat the volume of effluent to be disposed of (its hydraulic capacity) and thecapacity of the land to receive the nutrients in the effluent with removal ofresultant growth (its nutrient capacity). Webb evaluated both.

He commented that he was "not confident of finding land with permeable soilswithin the radius." However, another investigation he had done forMilton had identified a potential land type there and "the fans 4 km to thesouth−east of Waihola" are a similar type. He thought that an applicationschedule of "around 23mm applied every 10 days" could be achieved.8 Thissite is approximately 6km from the present sewage treatment plant.

At this application rate and the average flow of 102 m3/d, the area required fordisposal is 4.45ha,9 in addition to which a buffer zone will be required. A 50mbuffer zone all round will add approximately 5.2ha to this, making a total of9.65ha all told. The location of this area is shown in Figure 5.

Trevor Webb, Soil Investigation to evaluate Capability o f land Surrounding Waihola,Kaitangata, Owaka, Clinton, Heriot and Lawrence f o r Use as Municipal

Disposal Sites (Manaaki Whenua Landcare Research, 2007)Webb. 11.Webb, 11, identifies an area o f 3.7ha is required but this is based on a daily flow o f The above

area is calculated pro rata from this based on the current average daily flow o f 102m3.

13

Figure 1. Soil map of land surrounding Waihola

Legend

•

Figure Possible Area for Disposal from Waihola Sewage Treatment

Webb, 12.

14

In order for an area in this vicinity to be developed for land based disposal, thefollowing work will be required:

• Construct new pump station at the sewage treatment plant to convey

sewage to the disposal site;

• Construct a new rising main from the sewage treatment plant to the

disposal site;

• Construct a new pump station and control system at the disposal area;

• Fence and landscape the disposal area; and

• Install reticulation to a means of disposal (eg spray irrigation).

This assumes that the present effluent can be disposed of to land (Webbcomments that tertiary treatment prior to land disposal is bestFurther treatment of the present effluent may be required before it can bedisposed of, but the cost of this is not included in this brief analysis.

The estimated cost of establishing land based disposal at this site is$2,110,000. A number of other considerations need attention before this figurecan be confirmed. Foremost among these are specific investigations todetermine that the area, which Webb described as likely to be suitable, isactually suitable for land based disposal. Other factors also need to be takeninto consideration:

(a) There will be a considerable operating cost in addition to the abovecapital cost.

(b) If the soils become saturated, then irrigation will not be possible asponding or runoff onto other or into waterways is likely tooccur. The only solution to this is to provide storage to bridge suchperiods.

(c) Whether treatment of the effluent is needed to make it suitablefor pumping over 7km and being applied over the disposal area.

It is clear that much work is required before this form of land based disposal isshown to be feasible, and even if this is demonstrated, the costs areconsiderable.

The cost given above does not make any allowance for extra costs fortreatment or storage, so may be optimistic. However, even at this level, it is ofthe order of twice the estimated cost of improved effluent treatment andcontinuing to discharge to the Outlet Channel. For this reason, this alternativehas not been evaluated

4.2 Continued Discharge to Water (Lake Waihola Outlet Channel)

The alternative to land based disposal is the continuation of the discharge tothe Lake Waihola Outlet Channel. There are no other locations for a point

Webb, 9.

15

discharge which appeal as having advantages over the Outlet Channel. Theenvironmental impact of the discharge has been assessed for Clutha DistrictCouncil on four occasions, in 1996, 2001 (twice) and 2014. The first was forthe purpose of supporting an application for the current consent; the secondand third for supporting a review of all Council's treated sewage discharges(also used in support of the 2002 consent application); and the fourth insupport of this current application.

In considering the earlier reports, it must be noted that, in a general sense,land use and farm intensities have changed since then. However, there isinsufficient water quality data to determine whether this has had an effect onthe water quality in the outlet channel.

In contrast, the discharge volume has increased. While no meteredvolumes are available prior to 2013, the resident population in the censusmeshblock which covers most of Waihola has increased from 231 in the 2001census to 300 in 2013, with the number of occupied dwellings increasing from99 to 141 in the same time. There are a number of to the ofWaihola not in the meshblock, which contribute an estimated 35 moreresidents. At present there are 172 connected to the sewer, whichincludes the school and the camping ground.

The 2002 application estimated flows, giving 66 and 200m3/d as the averageand summer flows, with the peak flow estimated as 799m3/d.

These compare to the present metered flows (2014−15), which show anaverage daily inflow of 93m3 and a peak inflow of 773m3. The average dailyinflow over December 2014 — February 2015 was 76m3, showing that theassumption that summer flows would be higher due to a higher populationmade in 2002 was not correct. The average daily outflow is 102m3. Thedifference between the average inflow and outflow can be accounted for fromrainfall on the pond and potential differences in pond and wetland levels.

Compared to the present day, the earlier assessments were considering alower volume of discharge from a single oxidation pond into receiving water.Hence, the 2014 assessment is the only relevant assessment, although theearlier assessments do hold some interest.

The then Ryder Ltd considered the issue in 1996.12 They notedthat the "lower Taieri River is the dominant factor affecting the hydrology andwater quality of lake Waipori and its channel" and concluded that "TheWaihola sewage discharge appears to be having no measurable affect onwater quality or aquatic biota in the immediate vicinity of its outfall."13

The 2002 consent application reviewed the environmental impacts assessedby the earlier and concluded that the "oxidation pond discharge has a

Ryder Ltd, Resource Consent Waihola Treated Sewage Discharge to LakeWaihola Channel, 1996.

13 Robertson Ryder, 17, 18.

16

effect on the water quality of the outflow adjacent lakesand the wetland complex."14

Ryder Consulting Ltd has completed an assessment supportapplication.15 The conclusion of that assessment is:

The discharge of effluent the Waihola oxidation pond to the outflowchannel of Lake Waihola has a minor effect on water quality that is restrictedto a localised area immediately downstream of the discharge point. This effectis temporary and shifts with the changing tide. The discharge does not appearto adversely affect aquatic plant, benthic macroinvertebrate, or birdcommunities. The minor and localised effect of the discharge on water qualityin the channel is expected to have minimal, if any, effects on waterquality and aquatic communities in Lake Waihola, the surrounding wetland, orthe lower Waipori and Taieri

As Ryder there is little water quality data from the outlet channel tothese observations. However, Clutha District Council did obtain eight

samples between February 1998 and September 2002 which were analysedfor BOD5, faecal coliforms, enterococci and suspended solids. Table 5 showsthe results of that monitoring, expressed as geomeans for each contaminant.

FaecalColiforms Enteroccoci Suspended

20m Upstream ofOutfall20m Downstream ofOutfall

1.4

1.6

23.9

27.6

Table 5: Contaminant Parameter Geomeans, Upstream to Downstream

These results need to be treated with care. First, there are only eight samples.Second, while "upstream" in the context of the table means towards LakeWaihola from the and "downstream" towards the sea, no record of thedirection of the current at the time of sampling was made. Neither was theactual time of sampling recorded. Thus, any comparison between upstreamand downstream results may not be valid, as the current at the timehave been from the downstream towards the upstream

However, the differences between the relative geomeans for each parameterare so small that the only conclusion that can be drawn is that the upstreamand downstream water quality measured by these measures is the same. This

4 MWH, Waihola Oxidation Pond Discharge Resource Consent Application and Assessment ofEnvironmental 2002, 17.Ryder Consulting Ltd, Waihola Oxidation Pond Discharge to the Lake Waihola Channel

Assessment Effects, February 2014.16 Ryder, 47.

Ryder, 10.18 Ryder, 42, makes a similar observation.

17

is shown by the difference being less than 10% of the standard deviation ofthe sample population for all parameters except for BOD5, where thedifference is 23% of the standard deviation. It is true that the volume ofeffluent discharged is likely to be 40% higher now than when the abovesampling was done, but such a difference is not expected to have anymaterial impact on the Outlet Channel.

This is before any improvement to the effluent is considered. Clutha DistrictCouncil is proposing to construct facilities to further treat the Waiholawastewater and has proposed consent limits below which the new facilitieswill achieve. These consent limits are compared with the present effluent inTable 6.

TotalPhosphorus

FaecalColiforms

Ammoniacal TotalNitrogen

pH BOD5 g/m3 g/m3 g/m3

Existing Plant 8.27 99.8 11.03 48700 25.9 41.0 208.0

Proposed Limits 9.0 20 10 260 20 35 30

Table 6: Existing Plant Contaminant Concentrations as percentiles Compared toConsent Limits Sought. Note that the bacteriological consent limit proposedis for E. not faecal coliforms.

A treatment process has not yet been selected, although two are underconsideration at present. Both are anticipated to meet the limits proposed,with the actual 90th percentiles somewhat less than the limits.

There is therefore to be a significant reduction in the contaminant load beingdischarged to the outlet channel, with the range of reductions from the abovetable being from 10% (phosphorus) to 99% (bacteriological). Thus, thepresent minor, localised effect of the effluent will be greatly reduced, if noteliminated.

A suitable plant to treat the Waihola STP effluent is expected to have acapital cost of approximately and annual operating costs between$40,000 and $60,000. While still a significant cost for a small community, thisis a considerably cheaper alternative than land based disposal, and is to bepreferred.

4.3 Conclusion

The preferred alternative is a continued point discharge with additionaltreatment. Clutha District Council is seeking a consent which specifies effluentquality standards to be met and does not specify any treatment process, butproposes effluent quality standards which are such that a 35 year consent canbe granted.

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5. Assessment of Effects on the Environment

The RMA requires that the assessment of effects is to be in such detail thatreflects the scale and character of the actual and potential effects the activitymay have on the environment. The actual potential environmental effectsassociated with the discharge have been identified as being effects on:

Water quality;

• Aquatic ecosystems;

• Natural Character and Amenity;

• Cultural values; and

• People and Communities.

In February 2014, Ryder Consulting reported on an assessment of theenvironmental effects of the current discharge as noted in 4.2 above. A copyof the report is included as Appendix 3 and it should be read in conjunctionwith this AEE and understood to comprise part of it. The discussion belowlargely the Ryder report, while expanding on it where appropriate.

The report indicates that the present discharge is having a minor effect on theLake Waihola Outlet Channel. The proposed improvement in effluent qualityand associated consent conditions will reduce this effect.

5.1 Water Quality

The discharge has the potential to adversely affect water quality. Ryderconsiders that "The discharge's greatest measured effect on water quality inthe channel is an increase in faecal bacteria numbers," although healso notes that the monitoring results available to him are Evenif the effluent discharge is responsible for an increase in faecal bacterianumbers downstream of 18 as the November 2013monitoring the proposed improvements in effluent quality definedby suggested consent conditions will almost completely eliminate anyincrease in bacterial concentrations in the Outlet Channel due to thedischarge, measured by E. coli concentrations.21 This will allow the potentialfor the Outlet Channel water to meet contact recreation standard withoutbeing compromised by this discharge.

RyderIbid.

21 The current consent requires faecal coliforms to be monitored; it is expected that the new consentwill require coli, a species of faecal coliform, to be monitored. In practice, concentrations o f eachare essentially equivalent, although theoretically the numbers o f E. coli in a sample should be lessthan the total numbers o f faecal coliforms.

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There was little to no impact in the Outlet Channel from other contaminantsaccording to Ryder,22 so the improved effluent will certainly have no impact onthe channel.

5.1 Effect on Aquatic Ecosystems

5.1.1 Aquatic Algae and Plants

Ryder comments that there is "no detectable increase in phosphorus ornitrogen in the channel downstream of the outfall" so it is "unlikely that algaeand aquatic plant growth will be exacerbated by the discharge."23

5.1.2 Benthic Macroinvertebrates

Ryder notes that high ammonia concentrations can be toxic to fish andmacroinvertebrates but that ammonia levels are significantly lower than toxiclevels specified by ANZECC and ARMCANZ (2000) guidelines downstream ofthe outfall. pH levels are generally within guideline levels and the suspendedsolids discharged are unlikely to change substrate conditions in the

While the bottom of the allowable pH range proposed at 6.0 is somewhatbelow the mean from Clutha District Council's monitoring of 7.46, theminimum pH measured in that record is 6.69, so the reduction is not greatcompared to that. Ryder makes no comment on this specific limit, but CluthaDistrict Council considers that the proposed limit will have no measurableimpact on the pH in the Outlet Channel.

Overall, the proposed upgraded Waihola STP effluent discharge is unlikely tohave any adverse effect on the macroinvertebrate communities of the OutletChannel.

5.1.3 Fish

Ryder notes the potential impacts on fish from high BOD5 concentrations,ammonia toxicity and elevated suspended solids concentrations. However, hisassessment is that the existing discharge is having negligible effect on theOutlet Channel in respect of these contaminants, 25 so the proposed upgradeddischarge will have no measurable effect on fish.

5.2 Natural Character and Amenity

The predominant effect of the discharge on the natural character of the LakeWaihola Outlet Channel is the potential discolouration of water. This reducesthe clarity of the water, thus detracting from the visual amenity and there maybe potential to bring the clarity below the guideline for recreational use.However, Ryder notes that the clarity in the Channel was slightly below(upstream and downstream of the in November 2013 monitoring,

22 Ryder, 42−43.23 Ryder, 45.24 Ibid.25 Ryder, 45−47.

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somewhat less than the ANZECC and ARMCANZ (2000) guideline of 1.6m.There was a minimal decrease 50m downstream of the outfall but clarity hadrecovered by downstream. He suggests the current discharge has littleeffect on clarity.26

Faecal coliform levels are generally well below the ANZECC and ARMCANZ(2000) guideline for sports and recreation in the vicinity of the

so the discharge is not having an impact on recreation in the OutfallChannel. The great improvement proposed for bacteriological quality in thedischarge will only eliminate an already minimal risk to the equivalent qualityin the Channel.

5.3 Cultural Values

It is acknowledged that the maintenance of water quality is a paramountresource management issue to Ngai Tahu. The RPW notes that the dischargeof contaminants to water bodies is offensive to Kai Tahu, sincewater is of spiritual and practical Therefore, the degradation ofany water body may undermine the relationship that Iwi have traditionallyenjoyed and seek to retain with water bodies.

In the context of this application, it is proposed to discharge contaminantsdirectly to the Lake Waihola Outlet Channel. The preferred cultural alternativeof disposal to land is not available for reasons of cost and over thetechnical suitability of land for disposal. This leaves only the point discharge.However, as discussed in 4.2, the proposed improvement in treatment will

limit the already minor effects on the Channel. Therefore, it isconsidered that the adverse effects of the discharge on cultural values will beminor and have been mitigated as far as is practicable.

Effect on People and Communities

The discharge can affect people and communities in three ways. Firstly, itallows for the efficient disposal of sewage from human habitation, thus greatlycontributing positively to human health and wellbeing in Waihola. This is theprimary reason for gathering, treating and disposing of sewage in the mannerdone in Waihola. While suitable treatment technologies are available,the dispersed nature of them and variable management of their efficiencymean that the communal solution is much to be preferred. Human health andwellbeing in Waihola is best served by allowing the discharge to continue andany alternative is not to be countenanced.

Secondly, it can affect human enjoyment of the receiving environment. Thiscan be by detracting from the recreational values of the Outlet Channel. Thishas been dealt with above.

The third factor is the impact on the community of additional costs imposed,and this is not to be understated. In the past, Clutha District Council has

26 Ryder, 4027 Ibid.

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insisted that all costs lie where they fall: that is, that Waihola pay all the costsof its sewage treatment system. However, this has been changed with allcosts now to be met equally by all properties connected to communal sewagedisposal systems. 2015−16 is the first year in a six year transitional period inrespect of this change.

This means the impact on individual properties of the upgrading works isameliorated by economies of scale. Nevertheless, the proposal will require anincrease in annual sewer rate income of about $66,000 in the first year of itsoperation, excluding GST. This is almost a 3% increase in total sewagedisposal costs for Clutha District. In today's low inflation environment, this is adistinct impact on ratepayers.

5.5 Conclusion

Overall, the improvements proposed to the discharge will mean that theadverse effects of granting the consent will be less than minor.

6. Monitoring and Consent Limits

Council seeks staged consent conditions:

Stage 1: Prior to the construction of any new treatment system, and

Stage 2: After construction of the new treatment system.

The current consent requires monitoring effluent parameters at six monthlyintervals. It is proposed that stage 1 will continue with this six monthlymonitoring and stage 2 will require monthly monitoring.

There will need to be a period to allow for selection of the treatment process,design and construction of the new system and finally commissioning of thesystem. Following this some allowance needs to be made to allow the systemto bed in satisfactorily.

Accordingly, a period of four years from the date of consent is suggested as asuitable period to allow these processes to be completed.

It is also suggested that the consent limits be 90th percentiles. Using apercentile will cope well with the natural variation of the discharge. It is alsosuggested that rather than a bare percentile, which would apply to thewhole sampling record, the limits are expressed as "no more than one samplein any 10 consecutive samples" which approximates a percentile. Thisapproach has two other advantages: first that compliance is judged on recentsampling so measures what is happening "now", and second that currentcompliance cannot be affected by historical samples.

The suggested limits are calculated so that the current discharge will becompliant and are the same as the limits applying to Council's most recentlygranted treated sewage discharge consents, at Heriot and Kaitangata, savefor a small reduction in the bottom of the pH range. They are set out in Table7 below.

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Parameter 48 Months after date ofconsent, 9 of any 10consecutive samplesnot to exceed

From 48 Months afterdate of consent, 9 ofany 10 consecutivesamples not to exceed

pH (range) 6.0 — 9.0 6.0 — 9.0

140 20

Total Phosphorus g/m3 12 10

Ammoniacal Nitrogeng/m3

40 20

Total Nitrogen No Limit 35

Total SuspendedSolids g/m3

300 30

E. coli 100,000 260

Table 7: Proposed Consent Limits

In addition to these limits, a condition related to stormwater infiltration couldbe considered if the peak flow is excessive compared to the average flow.Reducing flows if this is the case can have a benefit for treatment systemsand reduces the volume discharged to the Outlet Channel.

However, stormwater infiltration is only considered excessive if the peak flowis more than five times dry weather flow. At Waihola, the flow record covering793 days from February 2013 to June 2015 shows an average daily inflow of91 m3 and a maximum daily flow of 773m3. However, the flow exceeded400m3 on only 7 days in the period, 18−22 June 2013 (five days, maximum507m3) and 4 and 5 June 2015 (maximum 773m3). The latter rainfall wasexceptional and those flows cannot be taken as indicative of the condition ofthe reticulation in respect of stormwater infiltration. Accordingly, with the peakto average flow ratio only a little over 5 for the remainder of the record, theconclusion is that stormwater infiltration is within acceptable limits and nocondition of the kind noted above is warranted.

Condition 2(c) of the present consent requires that:

The consent holder shall undertake an investigation into the options forthe of effluent into Lake Waihola. This investigation shall

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specifically assess the possibility of reducing the period of time effluent isdischarged. The consent holder shall provide a final report on thisinvestigation to the Consent Authority prior to the expiry of this consent (1September The report shall detail the time for implementing anyproposed changes to the disposal regime.

This report has not yet been done. Accordingly, a consent condition requiringthe same report be finalised and forwarded to the Otago Regional Council by1 September 2017 is suggested.

Statutory Considerations

7.1 Introduction

This section sets out the statutory planning framework that applies to thisapplication. Relevant documents are the Resource Management Act 1991("RMA"), the National Policy Statement on Freshwater Management ("NPS"),the Regional Policy Statement ("RPS") and the Regional Plan: Water ("RPW").

7.2 Resource Management Act

Section 5 of the RMA seeks to promote the sustainable management ofnatural and physical resources. it states that activities must bemitigated so that adverse effects on the environment are avoided, remedied ormitigated. Section 6 sets out those matters of national that are tobe recognised, while Section 7 sets out "other matters" that Council is to have

regard to. Finally, Section 8 requires all persons acting under theRMA to take into account the principles of the Treaty of Waitangi.

For the reasons detailed in Section 5 above, it is considered that thedischarge will not adversely affect the matters outlined on Sections 5−8 of theRMA. The discharge will have little or no adverse effect on thecapacity of the Lake Waihola Outlet Channel and any ecosystems associatedwith it. Accordingly, it is considered that the granting of consent for thecontinued discharge, with appropriate conditions, will achieve the purpose ofthe RMA.

7.3 National Policy Statement

The NPS was gazetted on 14 May 2011 and took effect from 1 July 2011. Itsets out objectives and policies that direct local government to manage freshwater in an integrated and sustainable way, while providing for economicgrowth within set water quantity and quality limits.

The NPS consists of eight objectives and fifteen polices, which focus on waterquality, water quantity, the role and values of Tangata Whenua, and theprogressive implementation of the NPS. The objectives and policies ofgreatest relevance to this application are commented on below.

Objective Al requires that the capacity, ecosystem processesand indigenous species, including their associated ecosystems, be

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safeguarded in sustainably managing the use and development of land, andof discharges of contaminants.

Objective A2 requires the overall quality of freshwater within a region to bemaintained or improved, while:

(a) Protecting the quality of outstanding bodies

(b) Protecting the values of wetlands and

(c) Improving the quality of in water bodies that have beendegraded by human activities to the point of being

Policy A4 directs all Regional Councils to amend Regional plans, to the extentneeded, to include the following policy:

1. When considering any application for a discharge the consent authoritymust have regard to the following matters:

the extent to which the discharge would avoid contamination thatwill have an adverse effect on the capacity of

water including on any ecosystem associated withwater and

the extent to which it is feasible and dependable that any morethan minor adverse effect on water, and on any ecosystemassociated with water, resulting the discharge wouldbe avoided.

The RPW has been updated so as to be consistent with the policy outcomeaddressed under Policy A4 of the NPS.

The Assessment of Environmental Effects indicates that the discharge will notalter or have a more than minor adverse effect on the capacityof the lake Waihola Outlet Channel and its associated ecological values.Further, the discharge will not have a more than minor adverse effect on theriver's ecosystems and their ability to be sustained. This is particularly so oncethe proposed treatment upgrade is in place. This accords with Objective Aland Policy A4 of the NPS.

Part D of the NPS relates to the roles and interests of Tangata Whenua. Theobjective seeks to provide for the involvement of iwi and hapu and to ensurethat the values and interests of Tangata Whenua are reflected in themanagement of fresh water.

Clutha District Council recognises the interests of Tangata Whenua and theirconcerns associated with this and similar discharges. It has operated for manyyears a Wastewater Working Party which is a formal Committee of Council onwhich appropriate local iwi are represented. This gives an for localiwi to contribute to the application process in order to determine how best toensure their requirements are met, an which has worked very wellin the past. This application has not yet been considered by the Wastewater

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Working Party, but is of the same scale and character as the previous sevenapplications for the discharge of treated sewage made (or modified) by theClutha District Council since 2009 which were approved by the WastewaterWorking Party. Council therefore considers that iwi interests have beensatisfactorily taken into account, but will be convening a meeting of theWastewater Working Party in early 2016 where there will be an opportunity forthis application to be considered. Of course, iwi may have the

to consider the application formally through any notificationprocess considered necessary by the Otago Regional Council.

7.2 Regional Policy Statement for Otago

The Regional Policy Statement for Otago (RPS) sets the direction for thefuture management of Otago's natural and physical resources, in accordancewith the purpose and principles of the RMA. The objectives and policies of

relevance to the discharge are Objectives 6.4.2, 6.4.3 and 6.4.4 aswell as Policies 6.5.1 and 6.5.5.

In respect of Otago's water resources:

Objective 6.4.2 aims to maintain and enhance their quality so as toprotect their capacity to meet the needs of Otago communities;

Objective 6.4.3 aims to safeguard their capacity byprotecting their quantity and quality;

Objective 6.4.4 aims to maintain and enhance their ecological, intrinsic,amenity and cultural values;

Policy 6.5.1 aims to recognise and provide for the relationship Kai Tahuhave with them; and

Policy 6.5.5 aims to reduce the adverse effects of contaminantdischarges into them.

As discussed above, the treated sewage discharge, oncetreatment is upgraded, will not adversely affect the capacity ofthe Lake Waihola Outlet Channel. Neither will it adversely affect the ecologicalor amenity values associated with the Outlet Channel except to a minordegree. It will continue to contribute to the health and wellbeing of the Waiholacommunity by providing safe and hygienic disposal of human sewage, thuscreating a value associated with the Outlet Channel.

As shown above, the alternative of disposal to achieve theseobjectives and policies is not feasible.

7.3 Regional Plan: Water

The RPW covers the use, development and protection of fresh waterresources, the beds and margins of water bodies, and the issues associatedwith that use, development and protection. The policy framework of the RPWhas been significantly modified by Plan Change 6A. While the Plan Change is

26

focused on addressing the effects of discharges, it does signal amove away from policy support for the assimilative capacity of water bodies.However, Chapter 7 still provides policy support for the use of mixing zones(Policy

The objectives and policies of the RPW most relevant to the discharge areassessed to be Policy 5.4.2, Objectives 7.A.1, 7.A.2 and 7.A.3, and GeneralPolicies 7.B.1, 7.B.2, 7.B.6, 7.B.8, 7.C.1, 7.C.2 and

Policy 5.4.2 promotes the avoidance of adverse effects, but only as a firstpreference as remediation and mitigation are also enabled. The outcomebeing sought is for the values of significance to be given the appropriatedegree of protection. The discharge proposed will maintain the quality of thereceiving water and so not adversely affect the values listed under Schedule1. Consequently, it does not cut across the outcomes sought in the RPW.

Objective 7.A.1 aims to have good quality water in Otago's water bodies andenhance that quality where it is degraded. Objective 7.A.2 aims to enable thedischarge of contaminants to water in a way which maintains good qualitywater and natural and human use values ("good quality water" isdefined in Schedule 15). As set out above, the proposed discharge will notadversely affect the quality of the water in the Lake Waihola Outlet Channel.

Objective 7.A.3 aims to ensure that communities and individuals recogniseand manage the effects of activities on water quality, including cumulativeeffects. As set out above, the proposed discharge does contain contaminantsthat have the potential to reduce the water quality in the Outlet Channel.Having considered the nature of the proposed discharge, after theproposed treatment upgrade, it will not result in more than minor adverseeffects, cumulative or otherwise. This is largely due to the proposed effectiveremoval of bacteriological contamination from the discharge.

Policy 7.B.1 aims to ensure that water is of good quality by the target datesgiven in Schedule 15 by avoiding discharges of contaminants with noticeableeffects and allowing those which have minor effects or are term. Thepolicy does not refer to the assimilative capacity of water bodies or mixingzones and whether the noticeable effects occur prior to reasonable mixing.Clutha District Council considers the policy can be and should be interpretedto apply after reasonable mixing. The proposed discharge will not result inother than minor effects after such mixing, and there will be no visual impacton water quality, so would achieve the good quality water parameters given inSchedule 15. This is so when Policy 7.B.6 is considered.

Policy 7.B.2 seeks to avoid objectionable discharges that degrade natural andhuman use values, to Otago waters. This discharge is not objectionable someets Policy 7.B.2.

Policy 7.B.3 specifically allows discharges to water which have minor effects.As demonstrated above, this discharge has minor or less than minor effectsso meets this policy.

Policy outlines matters to consider when assessing the need for anymixing zone. The extent of any mixing zone in the Outlet Channel is difficult tomeasure because of the nature of the discharge and the receivingenvironment. However, any zone will be small and Clutha District Councilconsiders it appropriate to allow a mixing zone in view of the less than minoreffects on the outlet channel beyond any mixing zone.

Policy encourages the adaptive management and innovation to reducethe discharge and impact of contaminants on water quality. The proposedimprovements to treatment will greatly reduce the contaminant load getting tothe Outlet Channel and are proposed in recognition of the possible impacts ofthe discharge on the river.

Policy 7.C.1 encourages enhancement of the water quality of degraded waterbodies. Clutha District Council does not accept that its present dischargecontributes significantly to any degradation of the Lake Waihola OutletChannel water quality that may have occurred, beyond the limited impactimmediately at the point of discharge and the possible elevation of bacterialevels. Consequently, it proposes to upgrade the treatment to effectivelyeliminate bacteria from the effluent before it is discharged.

Policy 7.C.2 requires that when considering applications for consents todischarge contaminants to water that the Regional Council give regard to thenature of the discharge and the sensitivity of the receiving environment toadverse effects; the financial implications and comparative environmentaleffects of other alternatives; and the current state of technical knowledge andthe likelihood that the proposed method of discharge will be successful.

The alternatives and their impacts are considered under Sections 4 and 5above. The conclusions drawn there indicate that the proposed discharge isthe best practicable option and is appropriate to the receiving environment.

This conclusion is reliant to some extent on reasonable mixing occurring in thechannel to integrate the discharge into the Outlet Channel. Policy aimsto limit the extent of a mixing zone to take account of a number of factors. Theproposed discharge will not result in a mixing zone that will diminish oradversely affect the values set out in the Policy, particularly as the extent ofthe actual mixing zone is difficult to determine (that is, it is small and variablein extent). The mixing zone sought is therefore aligned with this policydirection and is appropriate.

The term of the consent sought is covered in Policy 7.C.4, which states thatthe duration of any new resource consent for an existing discharge ofcontaminants will take account of the anticipated adverse effects of thedischarge on any natural and human use values by an affectedwater body, and:

(a) Will be up to 35 years where the discharge will meet the water qualitystandard required to support that value for the duration of the resourceconsent;

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(b) Will be no more than 15 years where the discharge does not meet thewater quality standard required to support that value but willprogressively meet standard within the duration of resourceconsent.

(c) be no more than 5 years where discharge does not meet thewater quality standard required to support that and

(d) No resource consent, subsequent to one issued under (c), will beissued i f the discharge still does not meet the water quality standardrequired to that value.

Clutha District Council requests a 35 year n relation to policy 7.C.4 (a)of the RPW:

The application is for a new consent for an existing dischargewith a significant improvement to the quality of the discharge;and

The Schedule 1 values associated with the Lake Waihola OutletChannel were summarised in Section 2.2 above. For thereasons given in Section 5 above, the discharge will notadversely affect the amenity values of the Outlet Channel or thenatural and human use values identified in Schedules 1A,and of the RPW.

Plan Change 6A deleted reference to anticipated environmental resultspreviously set out in Section 7.9 of the RPW. As such, there are noanticipated environmental results now prescribed supporting the policyframework contained within Chapter 7 of the RPW.

Plan Change 6A imposed receiving water quality standards and dischargewater quality limits which are set out in proposed Schedules 15 and 16respectively. The Lake Waihola Outlet Channel is not scheduled, but LakesWaipori and Waihola are, with the limits set out in Table 8.

Totalnitrogen

Totalphosphorus Ammoniacal

ml)Turbidity(NTU)

Receiving water: 0.55(31 March

2025)

0.033(31 March

2025)

0.1(31 March

2012)

126(31 March

2012)

5(31 March

2025)

Permitted ActivityDischarge Limits

1.0

nitrogen, 1April 2020)

0.035(Dissolved

reactivephosphorus, 1

April 2020)

0.2 (1 April2020)

550 (1 April2020) NA

Table 8: Water quality standards and permitted activity discharge water quality limitsfrom Schedules 15 and 16 respectively of the ORC Regional Plan: Water forOtago (2015). Timeframe for each parameter in brackets.

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The proposed discharge does not comply with the limit for ammoniacalnitrogen and will not comply with the dissolve reactive phosphorus limit basedon total phosphorus monitoring results. However, once upgraded, it willcomply with the E. limit. These limits apply for permitted uses so they arenot relevant in any determinative way in respect of this application. What isrelevant is that the assessment of effects shows that the effect on the LakeWaihola Outlet Channel of the discharge will be no more than minor.

Kai Tahu ki Otago — Natural Resource Management Plan 2005

The objectives and policies most relevant to the discharge are:

• Objectives and 5.3.3.iv. The former seeks no discharge ofhuman sewage directly to water and the latter seeks a reduction incontaminants discharged to water; and

• Policies 5.3.4.8 and 9. The first requires land based disposal for humaneffluent and the second the consideration of alternatives in renewals ofdischarge consents.

For the reasons given in Section 5 above, it is considered that discharge toland is impractical at Waihola, which leaves only a discharge to water as analternative. However, the proposed treatment will improve effluent quality andso any adverse effects of the discharge on the Lake Waihola Outlet Channelwill be no more than minor. Consent conditions and any continuing receivingwater monitoring will confirm that the effects of the discharge will continue tobe minor.

8. Consultation

Council has not made this application available to local Fish and GameOtago or the Department of Conservation through its Wastewater WorkingParty process but it is similar in approach and scope to all its recentapplications. Hence there was assessed to be no need for consultationthrough the Wastewater Working Party in this instance. However, it isintended to convene a meeting of the Wastewater Working Party in the newyear when this application will be considered. From the Assessment ofEnvironmental Effects, the impact of the discharge, onceupgraded, will be no more than minor, so any consultation is notrequired.

9. Conclusion

Proposal

The proposal is that the present treated sewage discharge to the LakeWaihola Outlet Channel continue with the addition of treatment toreduce the contaminant load discharged to the channel, with consent granted

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for a 35 year term. The above assessment shows that the activity will have noadverse effect on the environment, particularly once further treatment is inplace.

This has been identified by reviewing the effluent and receiving watermonitoring results and through an Assessment of Environmental Effects doneby Ryder Consulting. Once the proposed additional treatment is in place, theimpact on the Outlet Channel will be no more than minor, so consent can begranted for the discharge to continue.

9.2 Notification

As this is an application for the renewal of an existing activity, Clutha DistrictCouncil does not consider there are any circumstances which require that itbe publically notified. Council instead considers that if the Otago RegionalCouncil considers interested need have the to comment,then the most effective and timely way of proceeding is through limitednotification and so requests that this application be dealt with in that fashion inthose circumstances.

10. References

• Climate Change 2013: The Physical Science Working Groupcontribution to the IPCC Fifth Assessment Report; Projections of SeaLevel Rise, IPCC, 2013.

• MWH, Waihola Oxidation Pond Discharge Resource ConsentApplication and Assessment of Environmental Effects, 2002.

• Ryder Ltd, Resource Consent TreatedSewage Discharge to Lake Waihola Outflow Channel, 1996.

• Ryder Consulting, Waihola Oxidation Pond Discharge to the LakeWaihola Channel Assessment of Environmental Effects,February 2014.

• Webb, Trevor, Soil Investigation to Evaluate Capability of landSurrounding Waihola, Stirling, Kaitangata, Owaka, Clinton,Heriot and Lawrence for Use as Municipal Wastewater Disposal Sites(Manaaki Whenua Landcare Research, 2007).

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